Overload couplings



Aug. 28, 1956 B. RTHINGER OVERLOAD COUPLINGS 2 Sheets-Sheet l Filed NOV. 18, 1952 Aug. 28, 1956 B. RTHINGER OVERLOAD COUPLINGS 2 Sheets-Sheet 2 Filed NOV. 18, 1952 INPE/V70@ ERTHoLD RuTHlp/@ER Pf6. fa

United States Patent O ovnRLoAn coUPLlNGs Berthold Rthinger, Pforzheim, Germany, assigner to Karl Wezel, a firm Application November 18, 1952, Serial No. 321,074

4 Claims. (Cl. 64-29) The present invention relates to overload couplings, and is especially directed to a coupling provided with a safety clutch which is particularly suited for use in the driving shafts employed in rolling mills.

When the press-rollers of rolling plants, for instance fouror six-roller rolling plants, are in operation, there frequently occurs because of too strong a reduction in cross-section a jamming of the material to be rolled, which easily may result in undue torsional strain on the rollers and breaking of the latter if no precautions are taken.

That is why it has already been the practice to arrange in the driving shafts of rolling plants so-called safety bolts which, when the permissible torsional strain is eX- ceeded, are sheared off. However, experience has taught that the arrangement of new bolts in the driving shafts takes up a comparatively long time, and that during this time the workmen are idle and no work is done.

Instead of employing the aforesaid safety bolts, it has also been tried to arrange in the driving shafts between the actuating gearing and the rollers, safety couplings which in case of overloading automatically become disengaged. Known couplings of this kind consist of a spring-pressed claw-rim provided with slide-surfaces and adapted for engagement in a cooperating coupling rim. In constructions of this type there occurs during the disengaging movement a sliding surface friction, lwhich requires a large disengaging area, that is to say, a considerable allowance regarding the overload limit to be adjusted. In addition to that the radial dimensions of these known couplings are too large, as naturally the diameter of the couplings has to be in accord with the diameter of the rollers and the distance between them. Furthermore, it is desirable that the disengagement takes place at an accurately predetermined torsional strain.

The disadvantages of the known constructions are overcome by the present invention, which is characterized by the feature that in the coupling-rim cooperating with the claw-rim rolls are larranged which are radially positioned in the rim and partly embraced by the displaceable claw-rim, so that during the displacing of the claw-rim rolling friction with line contact occurs. An arrangement like this permits in combination with additional inventive features, which will hereafter be described, an accurate adjustment of the disengaging range.

The rolls may be of cylindrical or conical shape. They may be arranged in radially extending recesses of the cooperating coupling-rim formed by the shoulder of a coupling part. The radially extending recesses may be formed by laterally open bores which on their outside are closed up by a covering sleeve. If cylindrical rolls are used, the bores are of correspondingly cylindrical shape. If concial rolls are employed, the rolls should preferably be cone-shaped only in their area of action and protected against radical displacement by cylindrical supporting journals.

The coupling member provided with the claw-rim may be shiftably positioned on a multi-edged portion of the other coupling part for displacement against the pressure Patented Aug. 28, 1955 of a spring, and may be constructed in such a way that the claw-rim embraces at the most half of the circumference of the aforesaid cylindrical or conical rolls. If the claw-rim is devised like this it will be enabled to pass, While rotating the rolls, slidingly over them, as soon as the turning moment to lbe transmitted is in excess of the normal. The portions of the claw-rim embracing the rolls may further be provided with bevelled or rounded shoulders, whereby the resistance to wear of the coupling will -be considerably augmented.

For the adjustment of the axial pressure of the spring which is bearing against the rear end of the coupling member provided with the claw-rim, an annular nut may be used, which preferably may be secured in position by a counternut. In addition to that, an exchangeable sleeve may be arranged between the aforesaid spring and the portion of the coupling part surrounded by it. It will be seen that in a construction like this the spring pressure controlling the disengaging action in case of overloading, can be regulated not only through shortening of the accommodation area of the spring, but also through substitution of the spring by a stronger one, that is to say, by a spring of larger cross-section. The provision of the annular nut further makes it possible to adjust the couplings of a rolling plant in such a way that harmonious working of the couplings is guaranteed.

In order to obtain that the coupling parts are forming an undivided entirety, the invention contemplates to provide the coupling part having the aforesaid shoulder with an olset shaft, and to devise the other coupling part carrying the coupling member provided with the claw-rim as an interiorly hollow shaft into which the aforesaid offset shaft extends and in which it is supported in position by means of an annular supporting member bearing against an inner annular shoulder formed by an enlarge-V ment of the hollow interior of the shaft, said annular supporting member being secured in position by a nut screwed onto the threaded end of the offset shaft.

While I have described my invention as taking a particular form, it will be understood that thevarious parts may be changed without departure from the spirit of the invention, and hence I do not limit myself to the precise construction set forth, but consider that I am at liberty to make such changes and alterations as fairly come within the scope of the appended claims.

My invention will be best understood from a consideration of the following detailed description taken in co'nnection with the `accompanying drawings forming a part of Vthis specification, and in which corresponding parts are referred to by the same reference numerals in all of the several views.

In the drawings:

Fig. l is a side elevation of an overload coupling fastened to the journal-end of one of the press rollers of a rolling plant; p

Fig. la is a central longitudinal section of the overload coupling of Fig. l;

Fig. 2 is a side elevation, partly in section, of the coupling means of the overload coupling of Figs. l and la, showing the claw-rim in disengaged position because of overloading;

Fig. 3 is a vertical cross-section on line III-III of Fig. 2, showing the radial arrangement of the cylindricalrolls in the shoulder of the one of the coupling parts;

Fig. 4 is a vertical cross-section on line IV-IV of Fig. 2, showing how the coupling member provided With the claw-rim is guided on a multi-edged portion of one of the coupling parts;

lFigs. 5 to 7 are detail views, showing the arrangement of the cylindrical or conical transmitting means in the shoulder of one of the coupling parts;

Figs. 8 to 13 are diagrammatical illustrations of various Figs. 1 and la.

2 and 4 were connected-with each other-by means of-d1iva set screw 30 is screwed into -the bore.

3 form-s of constructionof the power transmitting elements of the coupling, in transmitting position and in disengaged position because of overloading.

Referring now to the drawings in detail, the reference numeral 2 designates the ends of the-journalsof .areducing gear for the actuation of the rollers. Thejournal ends '2 as well as the journal-ends 4 of thedrivenpress rollers 5 vare four-edged Vand in customary :mannerconvexly shaped, as shown in the construction illustrated .in Heretofore the four-edgedrjournalends ingv shafts which for Ythat purpose were provided with suitable recesses at` their ends. In this way the alterations of the planes of the axes of rotation .resulting from the necessary adjustment `in'height of the -pressrollers were compensated for. The herein disclosed lcoupling -now takes'the place of the aforesaid driving shaft,1and, inaddition to compensating for the diierences in the planes of the axes of rotation, also etectsthe automatic interruption of the transmission of power, that is to say, of-the transmission of therturning moment, in case of overloading. i Y

From an inspection-of lthe embodiment illustrated in Figs. 'l Vand la it will be seen that upon the four-.edged journal-ends@ on the driving side ofthe construction Ian interio'rly hollow shaft-like .coupling :part 6 ahas 'been mounted, which on the driven side of vthe construction is coupled to a coupling part 7 pushed onto thefour-edged 'journal-ends i ofthe press-rollers 5 to be driven.

The coupling part7 on the driven sideof the construction is provided witha shoulders Yhaving radially arranged( therein a plurality ofvlaterally-open bores'9r adapted to receive a corresponding number of cylinderrolls 10. The'rbores 9 are closed up on the outside by acovering sleeve v'1FL pushed ontothe coupling part 7. The cylinder rolls Viti engage with the free portions of their cross-sections partly'in recesses`12 provided in the clawrim 13 of a coupling member 14 which is shiftably, but not rotatably mounted on the multi-edged guide sur-face 15 lofthe coupling part 6 for displacement on that coupling part 6 against the resistance of the pressure spring l16.V Theipressure spring 16 is at one end bearing against the rear end 17 of the Vcoupling member 14, .and'at its other en'd, against an annular stop member 19 Whichis adjustably secured in position with the aid of .the annular nut and countern'ut'l. Rotation'ofthe yannular stop member '19 is prevented by means .of the projection21 engaging in a-.groove Ztl in the coupling` part 6, The `nuts 18 serve as a means for vtine adjustment of the disengaging turning moment. interposed betweenthev outer surface ofthe coupling part 6 and thepressure spring v16is an exchangeable sleeve '22,.enabling the use ofpressure springs of different strength fortheroughadjustmentof The -annular supporting member 25gis provided with means forpreventing its rotational displacement-andis secured in position within I'the enlarged hollow-interior` of the coupling part 6 by the nut 27. screwed onto the threadf ed. end ofthe shaft 24. AThe nutv27 is provided-with a threaded transverse bore and a locking means in :form of i Setscrew '36 presses with its inner end against the threaded-.portion of the shaft 24 to ix the nut 2 7 on the shaft and toprevent loosening of the nut. It will be seen that acoupling of this kind can be produced and arranged in operatingposition as an undivided entirety. Y

The lubrication nipples v28 and. 29fserve-asameans 4 `for lubricating the parts which 'are in frictional `contact with each other. Y

As soon as the driving moment to be transmitted from the journals 3 of the actuating gearing to the press rollers 5 exceeds (for instance because of too strong a reduction in cross-section of the material to be rolled) the permissible moment of transmission in accord with the diameter of the coupling member 13, 14, the strength of the pressure spring 16, the diameter of the cylinderl rolls 10 and the volume of the portion ofthe'cylinder rolls 10 embraced by the claw-rim 13, then the coupling isputinto action. As indicated Vin Fig. 2, .the coupling member 13, 14 then moves along on the four-edged guide surface 15 of the coupling part 6-towardthe rightagainst'the pressure of the spring 16 and slidingly passes, in rattleflike manner, over the cylinder rolls 10 rotating in the laterally open bores 9. in this way it is accomplished that the actuating gearing and the coupling part 6 may continue to worlt at a predetermined.transmissible maximum .moment while the coupling vpart 7 andthe press-rollers are standing still. The actuating means maythen be stopped temporarily in order .to be `started agaiuas soon asfthe obstacle, for instance jamming of the goods to be rolled, has been taken care of.

lFig. 5.is another illustration, on .an enlarged scale, .of the .coupling part 7, .showing the shoulder .S provided with .the bores 9 and the .cylinder-rolls V16v-.supported` in the bores 9. It will be noticed that only! on one side of the coupling .part a roll 1) vhas been arranged in a bore `9, so .that on-the other side of 'thev part the laterallyopen bore9, whichis partly covered up .by thesleeve l11,.'is clearly discernible. instead of arranging cylindrical rolls 10in cylindrical bores 9 (Fig. 6) it is also .possible to arrangeconical rolls 10cm bores of corresponding shape 9a, whereby the conical rolls ltashould, in order ,to lavoid radial displacement, preferably-'be provided :withcylindrical supporting journals. For disengagingpurposes the cone-shaped rolls areof course better suitedthan the cylindrical.rolls,'but, on the other hand, the manufacture of conical rollsis more expensive than that .of cylindrical ones.

The diagrammatical illustrations .of'Figs 8 to 13show inlFigs. 8 and.9.tl1e.shoulderbearinga of .a roll A19in cooperation witha claw-shoulder. b, whim is embracing less than .halfof the circumference of .therollpbefore and during thedisengagingaction. in Figs. .1() and11.the shoulder -bearinga of vltheroll lttcorresponds to thatof the precedingtigures, while the .claw-.shoulder cis provided withrounded corners. In Figs. l2.and .13 the clawfshoulder d .is .likewise provided with .roundedcorners, but, dierently from the.clawfshoulders'ofFigs; 8 to'll, embraces half. of: the :circumference of thexrolLlt).

Whatlclaim as new and .desire tov secure by Letters PatentofftheUnited.States is:

1. 4An: overload coupling vparticularly .for .use in; rolling plantscomprising, in combination, a irst'couplingS-.part having one vrendradapted robe fastened on .the journal. end of.'a press roller and provided'at its opposite end Withan annular shoulder, and with. a cylindrical. shaft. projecting.V

Vportion forming an inner shoulderin :said secondcouplingpart, said second coupling part being adaptedctobe fastened at oneend 1- thereof on the journal endf .fan actuating gearing and having anotherendffacing .said coupling. rollers with ai guide surface; anannularsup- Y por-ting memberr-locatedin said enlargedl hollowfportion of said second coupling part and being xedly mounted about said cylindrical shaft for rotation therewith, said supporting member having a pair of annular faces, one of said annular faces abutting against said inner shoulder; an annular nut located in said enlarged hollow portion and being screwed onto said threaded free end of said shaft and abutting against the other annular face of said supporting member so as to connect said lirst and second coupling parts non-movable in axial direction away from each other and rotatable relative to each other; a coupling member provided at the forward end thereof with a claw rim and being mounted on said guide surface of said second coupling part shiftable in axial direction for cooperation of its claw rim with said coupling rollers; and a helical spring surrounding said second coupling part and engaging the rear end of said coupling member for urging said claw rim into coupling engagement with said coupling rollers.

2. An overload coupling as claimed in claim 4 and including locking means engaging said threaded free end of said shaft and said nut for holding the same in position.

3. An overload coupling particularly for use in rolling plants and comprising, in combination, a rst rotary coupling part having a projecting shaft end portion, said first coupling part having an annular face formed with an annular recess, said first coupling part being formed with a plurality of radially extending bores, each bore communicating with said annular recess; frusto-conical coupling rollers turnably mounted in said radially extending bores and projecting into said recess; a sleeve slidably mounted on the outer surface of said rst coupling part and closing said radially extending bores for retaining said rollers; means securing said sleeve to said iirst coupling part; a second rotary coupling part having a cylindrical axially extending bore rotatably supporting said shaft end portion; attaching means secured to said shaft end portion located in said bore of said second coupling part and engaging said second coupling part so as to prevent sliding of said coupling parts in axial direction away from each other; an annular coupling member mounted on the outer surface of said second coupling part slidable in an axial direction but non-rotatable relative thereto, said annular coupling member having a rim projecting into said annular recess of said rst coupling part and being formed with recesses; and spring means mounted on said second coupling part engaging the same and said coupling member and urging the same in axial direction toward said annular face of said tirst coupling part so that said recesses in said rim embrace said rollers and connect said coupling parts for rotation, While said coupling rollers urge said coupling member in an opposite axial direction when the transmitted torque exceeds a predetermined limit whereby said coupling parts are dis connected for relative rotation.

4. An overload coupling particularly for use in rolling plants and comprising, in combination, a rst rotary coupling part having a projecting shaft end portion having a threaded free end portion, said first coupling part having an annular face formed with an annular recess, said first coupling part being formed with a plurality of radially extending bores, each bore communicating with said annular recess; coupling rollers turnably mounted in said radially extending bores and projecting into said recess; a sleeve mounted on the outer surface of said rst coupling part and closing said radially extending bores for retaining said rollers; means securing said sleeve to said iirst coupling part; a second rotary coupling part having a cylindrical axially extending bore rotatably supporting said shaft end portion, said cylindrical axially extending bore having a transverse shoulder and an enlarged portion housing said threaded free end portion of said shaft; an annular supporting member located in said enlarged portion of said bore and being fixedly mounted about said shaft for rotation therewith, said supporting member having a pair of annular faces, one of said annular faces abutting against said transverse shoulder; a nut located in said enlarged portion of said bore, being screwed onto said threaded free end portion of said shaft and slidably engaging the other annular face of said supporting member so as to prevent movement of said coupling parts in axial direction away from each other; an annular coupling member mounted on the outer surface of said second coupling part slidably in axial direction but non-rotatable relative thereto, said annular coupling member having a rim projecting into said annular recess of said iirstcoupling part and being formed with recesses; and spring means mounted on said second coupling part engaging said coupling member and urging the same in axial direction toward said annular face of said rst coupling part so that said recesses in said rim embrace said rollers and connect said coupling part for rotation, while said coupling rollers urge said coupling member in an opposite axial direction when the transmitted torque exceeds a predetermined limit whereby said coupling parts are disconnected for relative rotation.

References Cited n the tile of this patent UNITED STATES PATENTS 1,518,634 Cason Dec. 9, 1924 1,657,274 Niedhammer Ian. 24, 1928 2,432,633 Sirp Dec. 16, 1947 2,523,584 Miller Sept. 26, 1950 2,561,136 Richardson July 17, 1951 FOREIGN PATENTS 110,543 Switzerland 1925 89,743 Sweden 1937 

